A while back, SKS sent us these two mini bicycle pumps to review…and for three months, I had only one flat, and of course, I didn’t bring either on that particular ride.  So, finally, I just decided to deflate some tires and give them a whirl.
From a technical standpoint, both pumps are great.  The Puro (left) twists open to review the valve hole, and when you open it up, it has a built-in pressure gauge that measures both Bar and PSI.  It’s a fine example of German design.  The Sub-40 is a ridiculously light pump, with our model weighing in at just 38 grams!
Both are Presta-only and are intended for avid and elite cyclists; they’re not really for the novice or casual rider.  They’re very cool, but do they work?
Read on for pics, details and video of the Amazing Exploding Pump!
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Here’s what you get.  The Puro (above) comes with a bottle-bolt mount that positions it adjacent to a water bottle cage.  The Sub-40 (below) comes with a stretchy adjustable strap that can mount to any tube or post on your bike.
The Puro’s packaging claims 80g, our model weighed in at 82g.  Fairly light considering the features hidden within, which we’ll get to in a minute.
The Sub-40 had a claimed weight of 39g, but ours beat that at 38g.  Throw this in your jersey pocket and you forget it’s there.  It uses their ThinSkin technology, which is basically fiber-reinforced plastic to allow for very thin tube walls, which helps it achieve such a light weight.
The Puro measures only 7-5/8″ long when closed.  Twist it open and the top pops out and extends to 11-7/8″, giving you about 4″ of stroke.
The black bit at the right end of the orange tube is the pressure marker.  It slides out as you pump to show tire pressure.  The clear tube that comprises the shaft of the pump has markings for both BAR and PSI.
Here’s the valve head on the Puro poking out of the top.  The rubber seal keeps gunk from getting down in there when closed, but it tends to slip off when you’re holding it against the valve and pumping.
The Sub-40 measures slightly longer on both counts.  7-3/4″ long closed and huge 13″ fully extended.  The handle slides over the body when closed, hiding some of the extra stroke.
The Puro retails for $22.99 (with a carbon version for $44.99).
The Sub-40 retails for $49.99 and is also available in black.
Now, on to performance.  Rather than drone on about how they pump, I’ve prepared these little videos showing you.  Fair warning, this is not my best voice work (it’s cold and I’m a little sniffly), but it does the job of illustrating the pros and cons.
VIDEO #1: SKS Pumps on Road Tires (High Pressure)
VIDEO #2: SKS Pumps on MTB Tires (Low Pressure)
Bikerumor.com Rating
It’s a mixed bag on these two. Neither one performed well on the road bike with higher pressures, even when starting as low as 60psi.  But they do have some redeeming features, and each one is rated separately.  Let’s start with the Puro first:
SKS PURO MINI PUMP:
The Puro has a claimed max pressure capability of 10 bar/144 psi.  I’ll be honest, there’s no way I would use this to pump it anywhere near 144psi…it would simply take too long.  Besides, mini pumps are really just intended to let you finish a ride, not to inflate to max pressure, so there’s not much point in it other than to suggest that the pump is overbuilt.
One the one hand, this pump is super cool.  The hidden pump head is very James Bond, and the pressure gauge mostly works, which is nice, and it’s fun to show it off.  But, do you really need to worry about accurate pressure for a mid-ride fix?  Maybe, if you’ve got a long way to go, I suppose.  Lastly, it forms an OK seal on the valve.
On the other hand, it just doesn’t pump very much air per stroke, and it’s a little awkward to hold on the valve.  I was constantly afraid I would rip the tip off the valve stem and ruin my tube.  Seriously, after about 100 strokes, it maybe put 3-4 psi in a mountain bike tire.  So, even though the features are really cool on this one, I just wouldn’t see myself picking this one out of the other mini-pumps laying around the office.  I give it 2.5 Thumbs Up because even though it looks good, it works OK and it’s cheap, it’s just not as much fun to use as the features might suggest.
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SKS SUB-40 MINI PUMP:
I like the Sub-40 better, despite the “blowout” that occured during the road testing, and here’s why:  For mountain bike rides and commuting (with fatter tires), it does what it needs to do and it’s so insanely light that it doesn’t even register.  It formed a pretty good seal on the valve stem, and it had decent stroke feel, translating most of my effort into increased air in the tube.
However, on higher pressure road tires, this pump is worthless…and I’m soooo glad I didn’t have a flat when “testing” it on my road rides.  Not only is it really hard to push air in at mid- to high pressures, it tended to get stuck on the valve stem and/or blow apart.
Had it not blown apart, though, I wouldn’t have seen just how simple the pump is, which is a good thing.  There’s not much to break, and it snapped back together quickly and easily, which could come in handy in the woods.
My opinion is this:  I will now carry this pump on all mountain bike rides as a supplement to CO2’s.  If SKS had said this is a MTB pump only, I would have given it a 4.5 Thumbs Up.  But, since the package claims a max pressure of 144psi*, and since there is no possible way I could have pushed this thing in above 100psi, it gets a 3.5 Thumbs Up.  For riders that want to only buy one mini pump for both road and mountain use, this isn’t it.  If you only ride fat tires and you’re a weight weenie, buy it now.
* Actually, their website claims 116psi max, but packaging we received claimed 144psi.
ADDITIONAL NOTES:
It’s worth noting that these opinions shouldn’t necessarily reflect on the SKS brand, just these products.  Mountain Bike Magazine has rated SKS one of their Reader’s Choice “Best Brands” for seven straight years, and the Puro won a EuroBike award in 2008.  We have some other SKS products in the Review Queue that I’m anxious to try, and they have quite a broad portfolio of accessories.
As always, filter our reviews through your lens…if you don’t use products the same way we described in our review, it may not apply.
As mentioned in the review, I didn’t get a lot of flats, so long-term durability isn’t considered in this review.
